Musical digital interface instrument



FIG. 1 is a top, front and right side perspective view of a musical digital interface instrument showing my new design;

FIG. 2 is a front elevational view;

FIG. 3 is a top plan view;

FIG. 4 is a left side elevational view;

FIG. 5 is a bottom plan view; and,

FIG. 6 is a rear elevational view thereof. 

The ornamental design for a musical digital interface instrument, as shown. 